The venous system contains numerous one-way valves for directing blood flow back to the heart. Venous valves contain leaflets, with each leaflet forming a reservoir for blood which, under retrograde blood pressure, forces the free surfaces of the leaflets together to prevent retrograde flow of the blood and allow antegrade blood flow to the heart. When a valve becomes incompetent, the leaflets of the valve are unable to close because the leaflets fail to form a proper seal and retrograde flow of the blood cannot be stopped. Incompetent valves increase the strain and pressure that occurs within the lower venous sections and overlying tissues, sometimes leading to additional venous valve failure.
One particular condition that results from incompetent valves is varicose veins. Varicose veins often involve incompetence of one or more venous valves. Venous valve incompetence allows reflux of blood within the venous system and can cause dilation and tortuosity of veins, particularly within the superficial veins of the lower limbs. Besides cosmetic problems, varicose veins can be painful, especially when standing or walking. Additionally, varicose veins can cause discoloration, itching, and swelling. If left untreated, varicose veins may cause medical complications such as bleeding, phlebitis, ulcerations, thrombi, and lipodermatosclerosis.
Treatment of varicose veins includes both non-surgical and surgical treatments. Non-surgical treatments include, elastic stockings, elevating the legs, and exercise. While providing temporary relief, non-surgical treatments do not correct the underlying medical issue, which is the incompetent valve. Surgical treatments for varicose veins include vein stripping, ambulatory phlebectomy, vein-segment transplant, and thermal ablation. Thermal ablation includes delivering energy, e.g. radio frequency (RF) energy, to the vein to remove the incompetent valve from circulation by occluding the vein. While effective in treating the incompetent valve, thermal ablation involves many injections along the length of the vein to be treated and can be painful and time-consuming. Additional drawbacks with thermal ablation include the risk of damaging surrounding tissue.